TEST 4 STUDY GUIDEPassive margin: no relative movement btw. continent and oceanActive margin: 2 continents coming together, separated by deep ocean trenchTrench: convergent boundaries where lithospheric plates subduct into the mantle- long, relatively narrow- deepest parts of ocean (most >8km; 11km)- most are in PacificContinental shelf: extension of adjacent continent. narrower on active margin- Broad, flat from shoreline to continental slope- .05 degree slope- < 200 meters deep, may extend 100 km offshore- underlain by continental crust; NJ avg. shelf @135 kmCoastal plain: area that is drowned when sea level rises- 1:1000 gradient 1 meter sea level fall = 1 km under water Epicontinental sea: ocean that covers continent (90 million years ago)- western interior seaway, displaced water on continentGraded shelf: theory: currents become less instense further off shore, less turbulent- sand, then silt, then clay- graded bed – courser at bottom, finer on top, deposited at waning current- reality: sand covers edge of continental shelf b/c sea level changesContinental shelf break: characterized by markedly increased slope gradients to-ward the deep ocean bottom- shelf break may be as shallow as 20 metres (65 ft) and as deep as 550 me-tresContinental slope: don’t have a lot of sedimentSubmarine canyons: a steep sided valley cut into the sea floor of the continental slope, sometimes extending well onto the continental shelfTurbidity currents: form of underwater landslide, underwater density and gravity-driven - sediment flowsTurbidites: the rock/sediment produced by turbidity current, essentially a graded bedContinental rise: Abyssal plain: flattest places on Earth- 4 km water depth- forms largest part of ocean- contains submerged volcanoes called seamonts- away from tectonic processes, waves and tides at sea surface, turbidites com-ing off the shelfLithogenic: type of deep sea sediment- terrigenous (turdbidites) derived from continents/land- pelagic clay “red clay” – barren regions below the CCD with eolian, volcanic, and cosmic sources for mudHydrogenic: type of deep sea sediment- manganese nodules: - very slow growth (few cm per million years)Biogenic: type of deep sea sediment- derived from organisms like those below:o foraminifers – made of calciteo coccolithophorids – (chalk) calcite, photosynthetico diatoms – silica (siliceous), photosynthetico radiolarians - silica- carbonate ooze ( organisms more than 30% of sediment is an ooze)o more than 48% of the ocean floor, accumulates above CCD- siliceous ooze – sediments are concentrated in regions of upwelling ocean cur-rentsManganese nodules: found in many places of the seabedDistribution of sediments: dilution, destruction, productivityBiological production: reproduction of organismsDilution by other particlesDestruction by chemical: calcium carbonate dissolves (ccd – carbonate compensa-tion depths) red clays too deep for carbonateprocessesCarbonate compensation depth: - below CCD, water holds more CO2, resulting in more carbonic acid, dissolving CO2 fasterHydrologic Cycle: powered by sun, atmosphere provides the link, water from oceans carried onto land- on earths surfaceo run-offo evaporation, transpiration, infiltration (water that soaks into ground, source of ground water)Water reservoirs: any environment where water is stored- oceans: 96%, glaciers: 3%, groundwater: 1%, surface water (rivers and lakes):- .1%Groundwater: abundant: 70 times more fresh water below ground than above it- constant: available during dry periods- widespread: can flow from humid environments to where it is needed in dry regions- tends to move slowly, as seepage through pores of rock, soil, unconsolidated materialPorosity: the percent of the total volume of a rock that consists of pore spaces grains do not completely fill space- sizes and shapes of particles, compactness and arrangement determine poros-ity- igneous and metamorphic rocks have low porosityPermeability: the capacity for transmitting fluids, sands have high permeability- small holes/connectors do not allow water to pass through- clay/shall, little to no porosity- low porosity  usually low permeability BUT- high porosity  does not mean high permeability- in gravel, openings are large but stuff is of many sizes, pores get clogged- fractured shale has secondary permeability because of its fracturesInfiltration: water that soaks into the ground- source of ground waterWater table: top of saturated zoneZone of aeration: open spaces are normally filled with air (in soil)Zone of saturation: spaces are filled with waterAquifer: sediment/rock through which water flows easily (Ex: sand, gravel, limestone)Confining bed: sediment/rock that restricts flow of water (ex: clay)Perched water bodies: Karst topography: landscape which caves and sinkholes are so numerous they form a specific topography: - many small, closed basins- disrupted drainage pattern- streams disappearing into the ground- streams reappearing as large springsStalactites: icicle like coneStalagmites: upward pointing coneD’Arcy’s law: depends on 2 things- slope of the water table (steeper = faster)- permeability (higher = faster)Springs: location where the water table intersects the ground surfaceArtesian well: a well in which water rises about the aquifer. Sometimes pressure can lift the water above the ground and water will flow- well water pumped into holding tank, gravity maintains pressure from there tofaucet- Subsidence: over pumping can cause grains to settle  fissures and depressionsSalt water intrusion: pulling salt-water into fresh-water aquifersStream: a small, narrow river- a continuous flow of liquid, air or gasSheetwash: a film of water a few millimeters thick that covers a ground surfaceLongitudinal profile: stream features change from steeper at headwaters to flatter at the mouthDrainage basin: or watershed, a region drained by a single river or river systemDivide: a ridge that separates two adjacent drainage basins Base level: lowest elevation a streambed can reach at a given locality- streams erode their channel down to base level- ultimate base level is sea level- waterfall is an example of a local base levelDischarge: where groundwater flows from the surface- discharge = velocity x cross sectional area (width x depth)- when area decreases and discharge stays the same, velocity increasesCapacity: the ability of a given stream to carry sediment, measured as the maximum